1. Field of the Invention
This invention relates to an improved laminator. More specifically, the invention relates to an inexpensive packet-type laminator employing a pair of contact heating platens and a pair of compression rollers that can be readily disassembled, repaired or replaced, and then easily reassembled.
2. Description of the Prior Art:
With the advent of the packet-type laminable plastic pouch, the concept of sealing a driver's license, identification card, credit card, photograph or the like has become increasingly popular. Thus, it is generally known to place such an object within a packet between layers of thermoplastic sheet and then pass the entire pouch and contents through a small portable heat sealing laminator. After exiting the laminator, the packet is cooled and the outer protective layers are removed to recover the thermoplastic encapsulated object.
Various alternative methods have been proposed to improve laminators with varying degrees of commercial success. For example, in U.S. Pat. No. 3,711,355 a compact laminator involving an oven with spaced heating platens which do not make contact with the packet is disclosed. In contrast, U.S. Pat. No. 3,770,550 discloses a laminator that employs heating platens that not only make contact with the packet, but are also biased under pressure to squeeze the forward portion of the platens together as the packet passes through the laminator.
However, in the first case with no direct thermal contact between the heating element and the packet, heat transfer properties and thermal efficiency are not optimized, requiring unnecessary energy input at the heating stage. Similarly, if the contact heating element involves a force during laminating, drag is increased, leading to a decreased mechanical efficiency in that a larger motor is required to drive the packet between the heating platens.
In U.S. Pat. No. 4,451,320 the present inventor disclosed and claimed an improved motor driven packet-type laminator which featured an optimum balance between thermal contact and minimum drag and which could be readily and economically manufactured as well as easily disassembled, repaired and reassembled. The present invention is viewed as an improvement of the laminator disclosed in U.S. Pat. No. 4,451,320.